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I have a 2003 Bonneville SE with about 155k on it, for the last year it has pretty much been sitting since it decided to have a misfire on #1 cylinder. The codes that it had thrown in the past are PO301 and PO201 #1 Injector circuit open. The first mechanic down in Louisiana said it was a dirty MAF. No joy the codes reappeared a couple of days latter. Some off the things I did change where the coil pack, spark plugs and wires, injector, and ICM(which tested out weak). After moving back here to Pensacola I tried to have the car looked at, but my normal shop didn't find anything the first time I took it in. They had said to bring it back when it was misfiring again. About 3 weeks ago it did start it's misfire routine again and we took it to the shop and said that the head gasket was blown. Instead of paying the shop to do the job, I went ahead and did it with my neighbor who is a mechanic. I had the heads resurfaced and the valves done. The car has been running great until today when we where going to the store for groceries, upon start up it was misfiring again. I put the scanner on it and it had a PO301 and PO300 code, about an hour latter I went back outside checked the oil, antifreeze for levels and any mixing. The fluids looked fine, also checked around the gaskets for any fluid leakage. Started the car and the misfire isn't present now. About the only thing I haven't done is change the wiring harness, cam position sensor, crank position sensor, and PCM. If anyone has some thoughts I would appreciate it.

One other quick question, do the GXP tail lights have the same delamination problems as the standard Bonneville tail lights

Thanks

I'd change that plug again, it might have a crack in the porcelain causing the misfire. Also chances are it was just the LIM gaskets leaking. These cars almost never have bad head gaskets unless they were severely overheated.

It has a 33% chance that the same plug went back into the #1 cylinder. As far of the overheating part goes, I couldn't tell you what the girlfriend did while I was working out of town all the years we had it. God only knows what her daughter did to it either, she use to sneak out at night and take the car. only way mom found out was one morning the passenger seat had the hommie lean to it. If I could prove it the kid would have paid for half of the repair.

max harris wrote:It has a 33% chance that the same plug went back into the #1 cylinder. As far of the overheating part goes, I couldn't tell you what the girlfriend did while I was working out of town all the years we had it. God only knows what her daughter did to it either, she use to sneak out at night and take the car. only way mom found out was one morning the passenger seat had the hommie lean to it. If I could prove it the kid would have paid for half of the repair.

A little OT....

Some of us loathe Hommie lean, but some of us are actually a lanky largeish build as how that's the only way we fit.

...that and my passengers seat only has two modes
Vertical and Horizontal. No in-between.

mikeluscher159 wrote:

max harris wrote:It has a 33% chance that the same plug went back into the #1 cylinder. As far of the overheating part goes, I couldn't tell you what the girlfriend did while I was working out of town all the years we had it. God only knows what her daughter did to it either, she use to sneak out at night and take the car. only way mom found out was one morning the passenger seat had the hommie lean to it. If I could prove it the kid would have paid for half of the repair.

A little OT....

Some of us loathe Hommie lean, but some of us are actually a lanky largeish build as how that's the only way we fit.

...that and my passengers seat only has two modes
Vertical and Horizontal. No in-between.

I hear you on that. The kid wasn't that tall yet, at 20 now she's only about 5'9". Back then she wasn't that tall nor where her friends.

i think I may have this problem tracked down to the crank position sensor being flaky. Sometimes when starting the car with crank briefly and stop. Almost like years ago before there where sensors and the starter was going bad and hung up. Then you hit the key again and she starts up without a misfire. Sometimes when it starts right up it does its misfire right away shut it down and a half hour latter every thing is back to normal.